The present disclosure relates to a control device generating electrical signals for the control of an electronic appliance. Such a device is also called switch with multiple electrical switching channels. More particularly, the present disclosure relates to a control device with multiple switching channels, with tactile effect.
Recent developments and the rapid evolution of telecommunication means, such as portable radiotelephones, laptop computers and other devices that make it possible, for example, to play by accurately moving a cursor on a screen, and, for example, on the steering wheel of a motor vehicle, require the availability of electromechanical components of reduced dimensions and, in particular in the areas mentioned previously, the possibility to scan menus, move a symbol on a screen and, more generally, combine in a single component a plurality of electrical switching functions.
It is desirable to have a device that uses a single control member that makes it possible, on the one hand, to generate pulses or electrical signals repeated at high frequency and, on the other hand, to generate unitary signals, for example selection signals, and do so with a user-friendliness that is perfectly suited to this type of operation, that is to say which enables the user to easily and rapidly produce the repeated pulses, for example in order to perform a rapid scan of a menu or of a list, then to produce selection signals.
It is notably desirable for such a control member with multiple switching channels to be able to be manipulated with the thumb by being located on the front main face of the telephone notably comprising the keypad, or on one of the two main side edges of the telephone casing, or under the main face of the telephone. The same applies when such a control member is incorporated in the rim of a steering wheel of a motor vehicle, the manipulation having to be able to be performed reliably and blindly by the driver.
The need for a control device that is compact and of small dimensions that makes it possible to move a cursor on a screen, and/or to scroll menus (scanning), also called “navigator”, is becoming increasingly important for the control of appliances that are offering more and more functions and services notably involving options offered on one or more screens, in a manner similar to the use of a laptop computer.
It is also desirable to be able to have at least one selection function on which the user presses to select an option corresponding to the position reached by the cursor on the screen through the manipulation of a control member, notably in the form of a rotating drum. Furthermore, it is desirable to be able to have a very efficient navigator that makes it possible in particular to move around both with speed and accuracy.
Moreover, the tactile sensation transmitted by the device to the user of the navigator is a very important parameter for its efficiency and its user-friendliness. The sensitivity of the touch of the user is such that it enables him or her to perceive very fine, discrete or continuous variations, and it is thus possible to transmit to the finger or to the hand of the user a very complex “message”. The finger is thus a giver of commands (or sender) for moving the cursor on the screen and/or for selecting a position of the cursor, and it is also a sensor (or receiver) which “blindly” perceives tactile information in return via the actuator or control member of the control device, without therefore the user having to look at the screen and/or in addition to his or her visual perceptions.
It is thus desirable to provide the user with tactile sensations which are produced directly in response to the movement of the finger on the actuator, that is to say in its function as sender. In the case of a movement or scanning, such tactile information or sensations are, for example, mechanical pulses or “clicks” corresponding to each electrical signal or pulse produced by the navigator and intended for the electronic signal or data processing circuits of the appliance, or corresponding to series of pulses.
Other mechanical pulses or “clicks” correspond to the electrical pulses supplied to the electronic circuits upon a manual selection (select) action, for example when a target has been reached on the screen. Such a control device must now be able to be of the so-called five switching channels type, that is to say having a first and a second switching channels corresponding to the rotation of the control drum in one or other of the two directions of rotation, for example for vertical movements on a screen, a third and a fourth switching channels by pressing on the left or right end of the drum to move in corresponding directions on the screen, then a fifth so-called selection channel, when a target area has been reached, by pressing at the centre of the control drum.
It is necessary to be able to have a tactile sensation upon the generation of the signals associated with the third, fourth and fifth switching channels. Moreover, a significant enhancement of the reliability of this type of control device or navigator is required by the market, notably with regard to the dust-tightness of the electrical contact areas, which has led to this requirement being taken into account from the product design phase.
To this end, a control device has already been proposed that is of the type comprising a rotating horizontal shaft that can be driven in rotation, in both directions, by a manually driven drum borne by the shaft to which it is linked in rotation, of the type in which the shaft is linked in rotation to at least one rotating member belonging to a generator of control signals, or pulses, for an electronic appliance, to generate signals according to a first or a second switching channels notably to control movements of a cursor on a display screen of the appliance, and of the type in which the shaft is mounted to move vertically and pivot in both directions about a transversal horizontal axis orthogonal to the longitudinal axis of the shaft to selectively provoke the triggering: (1) of a triggering member belonging to a third switching channel when a distinct force is applied in the vicinity of one of the two longitudinal ends of the drum; (2) of a triggering member belonging to a fourth switching channel when a distinct force is applied in the vicinity of the other of the two longitudinal ends of the drum; and (3) of a triggering member belonging to a fifth switching channel when a (selection/select) force of vertical orientation is applied substantially at the centre (at mid-length) of the drum.
Design examples of such a device are, for example, described in France Patent Publication FR 2792486, the content of which is hereby incorporated by reference. In this document, three triggering members of bistable type are used, each making it possible to generate a tactile sensation when it is actuated to generate an associated signal. Such a design has the drawback of exhibiting the risk of simultaneous production of several “clicks”, that is to say several tactile sensations corresponding to the simultaneous or quasi-simultaneous actuation of two bistable triggering members, or moving contacts.
In order to prevent this phenomenon which is detrimental to the good user-friendliness of the control device, a hinge ball joint is used for the cradle supporting the rotating cylindrical drum, so as to mechanically “separate” the different “pivotings” of the support cradle. However, this solution is not satisfactory because it culminates in very poor user-friendliness when actuating in “selection” or “select” mode because it requires the user to apply his or her force to the drum in an almost pinpoint manner at a “central” point at axial mid-length of the drum, failing which the user accidentally generates “left” or “right” signals, instead of a “select” signal.
The present invention aims to propose a control device that uses only a single bistable control member supplying a tactile sensation reliably and unequivocally.